Naltrexone Can Trigger Severe Withdrawal in Kratom Users
Patients using kratom should discuss the risk of severe withdrawal with their doctor before starting naltrexone.
Updated on Oct. 21, 2026 in Substance Abuse
A 64-year-old patient required a 12-day hospitalization, including intubation, after experiencing severe withdrawal symptoms triggered by his first dose of naltrexone while using kratom daily. This rare but serious adverse reaction highlights a potential risk for individuals taking the opioid antagonist while consuming kratom.
Why it matters
Naltrexone is an opioid antagonist, meaning it can block the effects of substances that act on opioid receptors. For patients who use kratom regularly, this sudden displacement can cause acute, medically urgent withdrawal symptoms, complicating alcohol use disorder treatment plans.
This clinical case report describes a 64-year-old male with a daily kratom habit who developed severe withdrawal after a single 25 mg dose of naltrexone, resulting in a Naranjo score of 5, which indicates a probable causative drug reaction. Only three similar cases exist in the literature.
The details
Naltrexone works by occupying and blocking opioid receptors in the brain. Because kratom alkaloids also bind to these receptors, the sudden introduction of naltrexone effectively strips the receptors of kratom, causing an immediate, high-intensity withdrawal state. In this patient, the reaction was severe enough to cause tachycardia, extreme agitation, and high blood pressure, necessitating intubation when standard sedatives proved insufficient.
Timeline
2011-2017: 1807 kratom exposures reported to US Poison Control Centers.
Hospital day 2: Patient developed liquid stools and required a rectal tube.
Hospital day 7: Patient was extubated after initial respiratory support.
Hospital day 12: Patient was discharged to an intensive outpatient program.
Health Landscape
Kratom is estimated to be used by 0.7% of the U.S. population, with usage reaching 10.4% among those with opioid use disorder. This case underscores the need for clinicians to screen for kratom use before initiating opioid-antagonist therapies for alcohol cessation.
If you are prescribed naltrexone, it is critical to have an open conversation with your doctor about all substances you use, including herbal supplements like kratom. Disclosing this history is essential, as starting naltrexone while kratom is in your system can lead to severe withdrawal.
The takeaway
Naltrexone can trigger intense withdrawal symptoms in people who regularly use kratom. If you are starting a new medication for alcohol cessation, ensure your physician is fully aware of your supplement use to help avoid dangerous adverse reactions.
Further reading
For more information on the risks of drug interactions, visit our Substance Abuse section.
Source note: This article includes information reported by Medscape.
